Diversity of cultivable bacteria isolated from the water column and bottom sediments of the Kara Sea shelf

Microbiology ◽  
2012 ◽  
Vol 81 (4) ◽  
pp. 484-491 ◽  
Author(s):  
M. Yu. Suslova ◽  
I. A. Lipko ◽  
E. V. Mamaeva ◽  
V. V. Parfenova
1984 ◽  
Vol 19 (2) ◽  
pp. 97-109 ◽  
Author(s):  
R.J. Cornett ◽  
L. Chant ◽  
D. Link

Abstract The average annual flux of Pb-210 from the atmosphere to lake surfaces and to the bottom sediments was measured in seven small lakes located on the Laurentian Shield. Direct atmospheric fallout of Pb-210 was 136 ± 16 Bq m-2 a-1 Streams from the lakes' catchments input an additional 5 to 473 Bq m-2 a-1. Only 16 to 80 percent of the total input was found in the lake sediments. The fractional rate constant for Pb-210 sedimentation from the water column ranged from 0.25 to 5.3 per annum.


1994 ◽  
Vol 51 (12) ◽  
pp. 2739-2755 ◽  
Author(s):  
P. Campbell

A comparative mass-balance approach is used to describe and quantify phosphorus (P) cycles during the open-water season in two unmanipulated Experimental Lakes Area (ELA) lakes. A bimodal cycle generally prevailed, in which water-column total phosphorus (TP = total dissolved P plus sestonic particulate P) peaked just after ice-out and again late in the summer. Changes in mass of water-column TP were often much larger than corresponding net external inputs. Shifts of P to and from either zooplankton or fish in the water column do not explain the P residuals. Rather, the bottom sediments must have been adding P to the water column. Short-term regeneration of P from the bottom sediments also probably occurs in artificially eutrophied ELA lakes. The mechanism of regeneration is probably biological. Other aspects of P cycling and P stoichiometry are discussed, particularly in relation to nutrient control of population structure and the function of primary and secondary producers.


Oceanology ◽  
2021 ◽  
Vol 61 (5) ◽  
pp. 645-661
Author(s):  
A. B. Demidov ◽  
V. I. Gagarin ◽  
E. V. Eremeeva ◽  
V. A. Artemiev ◽  
A. A. Polukhin ◽  
...  

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
A. A. Osadchiev ◽  
En. E. Asadulin ◽  
A. Yu. Miroshnikov ◽  
I. B. Zavialov ◽  
E. O. Dubinina ◽  
...  

AbstractRiver discharge is the main source of terrigenous sediments in many coastal areas adjacent to estuaries and deltas of large rivers. Spreading and mixing dynamics of river plumes governs transport of suspended sediments and their deposition at sea bottom at these areas. Generally river plumes have very large synoptic and seasonal variability, which cannot be reconstructed from structure of bottom sediments due to their small accumulation velocity. However, bottom sediments can be indicative of variability of river plumes on inter-annual and decadal time scales. In this study we focus on the large Ob and Yenisei buoyant plumes formed in the central part of the Kara Sea. These plumes interact and mix in the area adjacent to the closely located Ob and Yenisei gulfs. Suspended sediments carried by these river plumes have significantly different geochemical characteristics that can be used to detect Ob or Yenisei origin of bottom sediments. Using new geochemical methods we revealed dependence between spreading patterns of these plumes and spatial distribution and vertical structure of bottom sediments in the study area. This relation is confirmed by a good agreement between local wind and discharge conditions reconstructed for 1948–2001 and vertical structure of bottom sediments.


2019 ◽  
Vol 57 (11) ◽  
pp. 1213-1220
Author(s):  
N. V. Kuzmenkova ◽  
V. V. Krupskaya ◽  
E. V. Duriagina ◽  
I. N. Semenkov ◽  
S. E. Vinokurov

2014 ◽  
Vol 65 (1) ◽  
pp. 70 ◽  
Author(s):  
Deniz Özkundakci ◽  
David P. Hamilton ◽  
Richard McDowell ◽  
Stefan Hill

The determination of organic phosphorus (P) compounds in lake sediments can provide information on the potential for internal P loading. Settling seston and vertical sediment core samples from highly eutrophic Lake Okaro, New Zealand, were collected during a mixed winter and stratified summer period, representing, respectively, when the water column was well oxygenated and when the bottom waters were anoxic. Samples were analysed with 31P nuclear magnetic resonance (31P NMR) spectroscopy, which showed that both bottom sediments and settling seston contained orthophosphate, orthophosphate monoesters and diesters, pyrophosphates, polyphosphates and phosphonates. Phosphorus concentration in settling seston increased ~2.5-fold in winter as a result of seasonally induced changes in phytoplankton biomass, with a marked increase in the concentration of orthophosphate. Several potentially bioavailable P compounds in the bottom sediments were identified that were likely to contribute to recycling of P from the sediment to the water column. An ‘apparent half-life’ was used to quantify the time scales on which these compounds were recycled to the overlying water column. Orthophosphate monoesters that include inositol phosphates were the most persistent P compound. On the basis of half-lives, high internal P loadings may persist for more than 20 years, potentially hindering restoration efforts in Lake Okaro.


2019 ◽  
Vol 57 (12) ◽  
pp. 1320-1326
Author(s):  
T. A. Goryachenkova ◽  
A. P. Borisov ◽  
G. Yu. Solov’eva ◽  
E. A. Lavrinovich ◽  
I. E. Kazinskaya ◽  
...  

1983 ◽  
Vol 40 (S2) ◽  
pp. s23-s33 ◽  
Author(s):  
E. M. Levy

Baseline levels of low molecular weight volatile hydrocarbons and petroleum residues in the Grand Banks area were measured in April 1981 with a focus on the Hibernia and South Tempest sites where exploration for oil was occurring. Concentrations of volatile hydrocarbons ranged from 0.41 to 1.80 nmol/L (geometric mean = 0.74 nmol/L) in the water column and 0.05–3.20 mmol/L in the surficial bottom sediments. The former, almost exclusively methane, were of recent biological origin, while the latter, which also contained ethane, propane, and butane, were probably related to petroleum. There was no visible evidence of surface slicks at the time, and floating particulate petroleum residues were absent from most locations. Concentrations of dissolved/dispersed petroleum residues in the sea surface microlayer ranged from 14 to 440 μg/L (geometric mean = 28.9 μg/L) and in the water column from 0.05 to 4.1 μg/L. Concentrations of petroleum residues in the surficial bottom sediments ranged from 0 to 7.3 μg/g. While these levels are among the lowest found anywhere in the waters and sediments off eastern Canada and in the eastern Arctic, there was evidence that the oil industry, even at the level of its activity at the time, was having a detectable impact on background levels of petroleum-related substances in the sea surface microlayer and the surficial bottom sediments.


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